An efficient synthesis of telechelic poly(N-isopropylacrylamides) and its application to the preparation of alpha,omega-dicholesteryl and alpha,omega-dipyrenyl polymers

Poly(N-isopropylacrylamide)s (PNIPAMs) with cholesteryl or pyrenyl moieties at each chain end (CH-PNIPAMs or Py-PNIPAMs) were prepared via end-group modification of alpha,omega-dimercapto poly(N-isopropylacrylamides), ranging in molecular weight from similar to 7000 to 45,000 g mol(-1) with a polydispersity index of 1.10 or lower. The telechelic thiol functionalized. PNIPAMs were obtained by aminolysis of alpha,omega-di (isobutylthiocarbonylthio)-poly(N-isopropylacrylamide)s (iBu-PNIPAMs) obtained by reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide in the presence of the difunctional chain transfer agent, diethylene glycol di(2-(1-isobutyl)sulfanylthiocarbonylsulfanyl-2-methyl propionate) (DEGDIM). The self-assembly of the polymers in water was assessed by fluorescence spectroscopy, using the intrinsic emission of Py-PNIPAM or the emission of pyrene added as a probe in aqueous solutions of CH-PNIPAM. (C) 2007 Wiley Periodicals, Inc.